In the cigarette and tobacco industry, there has been considerable development associated with the enhancement of tobacco, cigarette paper, and the production of a new and improved cigarette. To improve the flavor and aroma of a cigar or cigarette, flavorants have been added to the tobacco to enhance or alter the taste and aroma. In addition, tobacco substitutes have been blended with regular tobacco to enhance or alter the taste and aroma.
Briskin et al. (U.S. Pat. No. 3,608,560) discloses a smoking product of oxidized cellulosic material. The filler is made of cellulosic material containing combustible carbon. Martin et al. (U.S. Pat. No. 3,993,082) is a tobacco substitute made with cellulosic fibers and pulverized carbon. Kirkland (U.S. Pat. No. 3,461,879) teaches an oxidized cellulose tobacco substitute. The substitute is made of oxidized cellulose in the form of gauze or pulp that may be blended with other forms of cellulose, polymers or tobacco. Flavoring agents such as menthol, tonka bean, or powdered deer tongue or licorice may be added to the cellulose material.
Other cellulosic tobacco substitutes have been disclosed. Boyd et al. (U.S. Pat. No. 3,943,941) teaches a synthetic smoking product made of combustible flexible fibers and a volatile substance. The flexible fibers contain at least 80% carbon by weight, and the volatile substance may include flavoring agents such as formates, acetates, propionates and butyrates, terpineols or high molecular weight alicyclic alcohols, menthol, vanillin, or tobacco extracts. Boyd et al. (U.S. Pat. No. 4,044,777) is another synthetic smoking product comprised of flexible self-coherent carbonaceous material.
Carroll (U.S. Pat. Nos. 3,369,551 and 3,369,552) teaches a product and process for producing a tobacco substitute. The tobacco substitute is made from leafy plants such as lettuce, cabbage, broccoli, collard, kohlrabi, spinach, and papaya leaves. The product is made by stripping the leafy material of substantially all of its ingredients except the carbohydrates and nitrogen compounds. Flavorants may be added to impart the taste and aroma of tobacco.
Another area of development in the cigarette and tobacco fields is the development of flavored paper. The flavoring agents added to the cigarette paper may also enhance or alter the flavor and aroma of a cigarette or cigar.
Cogbill et al. (U.S. Pat. No. 4,505,282) discloses an inner liner wrap for smoking articles. The inner liner is comprised of combustible porous sheet of cellulosic fibers and finely pulverized porous carbon particles. Flavor materials may be added to the sheet at any point, but are preferably added to the slurry. The flavoring materials include St. John's bread, licorice, glycyrrhizin, ammonium glycyrrhizinate, Clary Sage Oil or Absolute, sclerolide, lupulin, vanillin, menthol, nicotine, and tobacco extracts. Cline et al. (U.S. Pat. No. 4,225,636) teaches a high porosity carbon coated cigarette paper and method for making the same.
Engineered or synthetic cigarettes have also been developed to enhance and improve the flavor and aroma of the cigarette. Bennett (U.S. Pat. No. 3,738,374) discloses a cigar or cigarette having a substitute filler. The cigar or cigarette has a tobacco substitute with a minimal amount of tar. The substitute is made of carbon or graphite fibers, mat, or cloth, associated with an oxidizing agent.
Owens Jr. et al. (U.S. Pat. No. 3,902,504) discloses an engineered cigarette. The invention is a modified cigarette incorporating a tobacco column having a tobacco substitute of shredded carbon filled paper with the tobacco in increasing amounts toward the butt end of the cigarette. These cigarettes are claimed to display a more level yield of constituents in the smoke from tip end to butt end when measured on a puff by puff basis.
Banerjee (European Patent Application 0270916) discloses a smoking article with an improved aerosol forming substrate. The smoking article uses an aluminum capsule within which carbon particles are located. The flavoring agents are adsorbed within the carbon and are emitted when heat is added.
Several problems exist when flavorants are added to tobacco or cigarette paper. Unless a flavorant is fully adsorbed by an active surface agent, such as carbon, the flavorant tends to migrate. When the flavorant migrates, it moves to other areas of the cigarette, such as the paper and filter. In conventional cigarettes, some flavorants such as menthol migrate to all parts of the cigarette. Since menthol will migrate, the carbon fuel source as described in Banerjee is a logical site for the menthol to migrate to, this migration could cause an "off taste." There are applications where it is desirable to lock in the flavor so it does not migrate. There are some advantages to locking in flavorants as some have unwanted odor or need to be unobvious.
The aroma may also be affected by flavorant. With time, flavorants may migrate to the adjacent packaging of the cigarette or cigar. The effectiveness of the flavorant may diminish with continued migration. When the flavorant migrates to the packaging or other areas of the cigarette or cigar, exposure to the atmosphere hastens the diminishing process. A box of cigarettes exposed to ambient air tends to lose its flavor very quickly. Thus, there is a need for complete adsorption of the flavorant onto a medium to eliminate the problems associated with migration.
Another problem arises when flavorants are added to tobacco and smoking articles. In a normal cigarette, added flavorants provide an inconsistent release of additional flavor or aroma as the cigarette is smoked. The first puff has a concentrated amount of flavorant, but as the cigarette is puffed, the flavorant decreases so that the last few puffs contain little or no added flavorant. Thus, there is a need for the controlled and reproducible release of flavorant from a medium when exposed to a known elevated temperature.